It’s not the bucket shadowing import, but rather the shared bucket access import.
It looks like Sync Gateway is performing an on-demand import upon retrieval of that doc, primarily because it thinks something else has written to that document since Sync Gateway, and so we need to update our metadata (by generating a new revision). This external write could be a Couchbase SDK, Eventing process, etc.
@glenn Do you know of any scenarios in which your document could be modified in the bucket, rather than through Sync Gateway?